The US Food and Drug Administration (FDA) has approved a supplemental indication for setmelanotide (Imcivree, Rhythm Pharmaceuticals) injection for chronic weight management in adults and pediatric patients age 6 and older with obesity due to Bardet-Biedl Syndrome (BBS).
Setmelanotide, a melanocortin-4 receptor (MC4R) agonist, is the first FDA-approved therapy for BBS, a rare genetic disorder that impairs a hunger signal along the melanocortin-4 receptor (MC4R) pathway.
BBS affects an estimated 1500 to 2500 people in the United States.
Individuals with BBS typically have obesity that starts at age 1 along with insatiable hunger (hyperphagia). Available weight management options are generally unsuccessful.
Other symptoms may include retinal degeneration, reduced kidney function, or extra digits of the hands or feet.
Setmelanotide received priority review, orphan drug designation, and breakthrough designation for this new indication.
As previously reported, in November 2020, the US FDA approved setmelanotide for weight management in adults and children as young as 6 years with obesity due to proopiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1), or leptin receptor (LEPR) deficiency confirmed by genetic testing — who also have impaired hunger signaling from the brain.
These individuals have a normal weight at birth but develop persistent, severe obesity within months due to hyperphagia.
The FDA approval of Imcivree for BBS “represents a significant milestone for Rhythm [Pharmaceuticals], validating our strategy of developing Imcivree for people with hyperphagia and severe obesity caused by rare MC4R-pathway diseases and allowing us to provide our precision therapy to an established community of patients living with BBS and their families who are eagerly awaiting a new treatment option,” said David Meeker, MD, chair, president and CEO of Rhythm, in a press release.
Safety, Effectiveness in 66-Week Trial in 44 Patients
The safety and effectiveness of setmelanotidewas evaluated in a 66-week phase 3 clinical trial that enrolled 44 patients age 6 and older who had a diagnosis of BBS and obesity — defined as a body mass index (BMI) ≥ 30 kg/m2 or ≥ 97th percentile for pediatric patients.
After an initial 14-week, randomized, double-blind, placebo-controlled treatment period, patients entered a 52-week, open-label period.
The trial met its primary endpoint and all key secondary endpoints, with statistically significant reductions in weight and hunger at 52 weeks on therapy.
After 52 weeks of treatment, patients taking setmelanotide lost, on average, 7.9% of their initial BMI.
61% of patients lost 5% or more of their initial BMI, and 39% lost 10% or more of their initial BMI.
In the 14-week, placebo-controlled treatment, on average, BMI dropped by 4.6% in the 22 patients treated with the study drug and dropped 0.1% in the 22 patients treated with placebo.
At 52 weeks, the 14 patients aged 12 and older who were able to self-report their hunger had a significant -2.1 mean change in hunger score.
Setmelanotide is associated with the following warnings and precautions:
Spontaneous penile erections in males and sexual adverse reactions in females. Instruct males with erection lasting longer than 4 hours to seek emergency medical attention.
Depression and suicidal ideation. Monitor patients for new onset or worsening depression or suicidal thoughts or behaviors. Consider discontinuing the drug if patients have suicidal thoughts or behaviors or clinically significant or persistent depression symptoms.
Skin pigmentation and darkening of preexisting nevi (moles). Examine skin before and during treatment.
Setmelanotide is not approved for use in neonates or infants. Serious and fatal adverse reactions including “gasping syndrome” can occur in neonates and low-birth-weight infants treated with benzyl alcohol-preserved drugs.
The most common adverse reactions (with an incidence ≥ 20%) included skin hyperpigmentation, injection site reactions, nausea, headache, diarrhea, abdominal pain, vomiting, depression, and spontaneous penile erection.
The FDA did not approve the company’s supplemental new drug application for setmelanotide in Alström syndrome.